Treatment of wax mixtures



Nov. 23, 1937.

s. w. FERRIS ET AL TREATMNT OF WAX MIXTURES Filed Aug. 21, 1955 3 Sheets-Sheet 1 A w ooo, m m mu w g w m o o N ED\ E Naum@ efractive Index ai 60Cl (7 5 u wsm m n rm& .w aw i UF aw a rF h a C t 5% Ma u? 9 1 SWH Nov. 23, 1937. s. w. FERRIS ET AL 2,099,683

TREATMENT OF WAX MIXTURES Fig w ///V6//// :L /l

/i /3//// V s v& /c,//,/// 5 0 g Eefracive Index ai 0 C (2 [nvenors Seymour WFe/v'is W'llardfi'Hou klan v Henry C Cola/e? Jr: 1 3

Patented Nov., 23, 1937 UNITED STATES 2,o99,6s3 PATENT OFFICE OF WAX x'rmss of Pennsy Application August 21, 1935, Serial Ne. 37,108

sciin.

The present invention relates to the treatment of solid or semi-solid waxy hydrocarbons, and relates more particularly to the separation of substantially oil-free waxy hydrocarbons derived 5 from petroleum, and petroleum distillates or residues, into fractions having diflerent physical properties.

An object of this invention 'is a process for the production of novel waxes or wax products .from

0 wax-bearing stocks or waxy hydrocarbon mixtures which have not heretofore been employed as a source of suohgnovel wax products.

A further object of this invention is a process .for the production of novei wax fractions which are substantially oil-free and diller from one another in melting point, crystal structure, hardness, plasticity and tackiness.

A further object of this invention is the production of novel wax fractions by sweatin;` substantially oil-free waxy hydrocarhon mixtures obtained from hydrocarbon oiis by methods other than sweating'.

A further object of this invention is the production of novel wax fractions by sweating substantially oil-free waxy hydrocarbon mixtures other than commercial parafllnwax obtained from paramn distillate by usua renning methods.

Briefly, our process consists in separating waxy hydrocarbon mixtures, which have heretofore been considered as unsweatable, into substantially oil-free i'ractions having different physicsl properties, and particularly different refractive indexmelting point relationships than waxes produced 'in accordance with the methods known and practiced by those skilled in the art. Our

process involves the sweating of waxy hydrocarbon mixtures which have not heretofore bee'n sweated, and more particularly our process is concerned with the separation of substantially 40 oil-free waxy hydrocarbon mixtures into fractions by sweating.

It has been known that crude petroleums, and particularly those of the so-called persian-base or mixed-base types, contain certain hydrocarbons commonly known as paraflln wax. such wax has been found to contain at least three fundamentally distinct crystalline types of wax, namely: plate, malcryst'alline and needle waxes. Present reflning methods, particularly sweatlng,

have a tendency to remove the malcrystalline and needle type waxes with the oil, and leave as solid the pl'ate type' waxes, so that the finished waxes tend for the most part to approach toward the plate type. In the usual methods of reflning crude petroleum, the crude is subjected to distillation thereby to separate it into a number of fractions of varying volatilities and viscosities. The fraction known as "paraflin distilla which, in general; is a frac'tion having a boillig range 60 of the order of rrom about 7o c. (sur r.) to

about 310 c. (m rc). when distilled undean absolute pressure of o m. m. Ofmercury, and which ordinarily is obtained from parai'iin base and mixed base crudes, is separated into a solid wax fraction and a iquid oll'fraction by chiiling and filter-pressing. 'nie solid fraction pr crude .w'ax collected in the filter press is known as "slack' wax", and contains a large qiantity of oil. This oil is removed or reduced by subjecting the slack was to a sweating' operation which consists essentlally in fractionally melting and draining the oil and lower melting waxes from higher melting waxes. The waxes resulting from the sweating operation are then further -reiined by any of the well-known processes. such as by treatment with sulphuric acid and/or per colation through fuller's earth. The products so] obtained are the ordinary paramn waxes of commerce. and are graded according to their melting points, into products diii'erlng in hardness and other properties. All of these products however, may. in general, be classed as hard and brittle, except at temperatures approaching their"` melting points; furthermore, they tend to crys- ,tallize rather coarsely.

After the parafiin distillate cut, usually there is separated from the crude during the distillation another higher hollin: cut, known as the high viscosity fraction. :Thisfraction also contains wax, but because of its particular crystalline form, it does not lend itself to separatlon directly byfllter-pressing; V Instead. this fraction is usually cold settled or centrifuced to effect a comparatively rough separation of the wax from the oil. The wax together with considerable oil. as it isseparated by the cold settling or centrifuging operation, is known as "petrolatum stock", and contains a micro-crystalllne form of wax generally known as slop wax". certain high melting waxesare occasionally obtained from "petrolatum stock" by repeated recrystallisations and settlings from naphtha solution. However. petrolatum stock cannot be successiully processed by either pressing or sweating. As a rulethe. wax in petrolatum stock is not recovered, but is cracked or otherwise disposed ot.

There are, in addition to the wat ource afore said, the residual stocks which contain a microcrystalline wax, commonly known as petrolatum wax. This was usually is not processed into a finished wax product, but becomes a slop was, or in some cases, after separation is employed in the production of petroleum jellies or the like.

v In the further treatment of slack wa: from the filter press. as referred to above in connection with the processing of "parailln distillates", the wax cake is melted and run into sweating pans, wher-ein it is cooled to a temperaturesubstantially below its melting point, and therealter heatedtocausetheoiloccludedintheslack wax to exude therefrom. The wax which is left after the first sweating is known as "crude scale" wax, and is usualLv resweated one or more times in the production oi' reflned waxes. The oil which exudes from this crude scale wa: on resweating, ca'rrles with it some waxes which roughly may be designated as "wax intermediates". These waxes are to a large extent lost from the final sweated wax products. Also, the oil passing from the wax in the first sweating, generally referred to as "foots" oil, carries with itsubstantial quantities of waxes which are in general not recovered.

It will be seen, therefore, that the usual methods oi wax recovery do not provide ior the recovery of many waxes which may be of moderately high-melting point, but which because oi their high solubility in the oil are sweated out with and retainedin the oil.

We have discovered that waxes which by prior processes remain in the oil, as pointed out above. may be recovered and upon recovery have hig ly desirable properties. Further, we have succeeded in preparing a series ot hydrocarbon waxes of very desirable properties quite diflerent from those ot the hydrocarbon. waxes heretoiore known. These waxes may be prepared !rom "roots" oil, or intermediate waxes from the sweeting operation, or from petrolatum stock or "slop wax", or in short, from practically any oil which contains waxes lost by customary methods oi wax recovery, of which methods those given above are typical.

It has been known heretotore to increase the melting point o! substantially oil-tree commercial paramn wax by sweating theretrom a portion of the lower melting waxes. It has likewise been known to obtain small quantities ot paramn wax from the "took" oil resulting !rom the initial sweating ot parainn slack wax, such process involving the concentration oi low meiting waxes by distilling a portion of the oil !rom the "toots" oil and thereatter sweating the resulting wax concentrate. Furthermore, it has been proposed to obtain high 'melting wax !rom petrolatum wax containing on' the order of 40% oil by distilling such wax to about 30% bottoms, diluting the distillate iraction with naphtha and filter pressing, and thereaiter sweating the resulting press cake containing on the order oi' 8%-10% oil to produce the high melting point wax.

Our process is distinguished from those of the prior art in that we sweat waxy hydrocarbon mixtures of a variety of types which have not htoiore been sweated, particularly substantialiy oil-free waxy hydrocarbons, to produce wax rractions having diflerent physicai properties. Moreover, the substantially oil-!ree wax !ractions produced in. accordance with our process have a markedly different relationship between refractive index and melting point than oil-free waxes obtained !rom the resweating of commercial paramn wax or wax mixtures derived i'rom conventionaliy sweated paramn slack wax.

In accordance with our invention. we may employ any method of preparing a substantially oilfree wax which does not involve sweating and consequent loss o! desirable constituents, and thereaiter subject the oil-tree wax so prepared to !ractional separation by sweating. However. !or a better understanding o! our invention, we describe a specific method without intending to limit ourselves thereto.

According to the process set !orth in a tao-pending application of S. W. marris, Serial No. 4157,

filed Jan. 29, 1935, we prepare an oil-wax mixture for example, by distillation, which upon cooling to the desired separating temperature will crystallize wax to the extent oi substantially 10% or less oi the total volume oi' the mixture; or we dilute a wax-bearing stock with a suitable solvcnt, so that upon cooling to ,the desired separating temperature, wax will crystallize to the extent o! 10% or less of the total volume of the mixture. The oil-wax mixture so prepared is then cooled to the desired temperature, with or without agitation, in such a manner as to eflect a dispersion of the wax crystals throughout the mother liquor with reasonable unitormity. If agitation is resorted to, the cooled mother liquor containing the wax crystals is thereatter permitted to stand, unagitated, for suiilcent time to eflect the formation oi a highly porous wax mass, the structure of which has appreclable mechanical strength, such mass containing less than substantiaily 10% oi solid wax per unit volume o! the mass. The displacement o! the mother, liquor !rom the cooled wax mass is then accomplished by passing a displacing liquid, prei'erably an -oil solvent, through the mass in such a manner that a substatially horizontal interface is maintained between the mother liquor in the mass and the displacing liquid, the displacement pressure (diflerentlai pressure or pressure drop through the wax mass) being of the order of 5 1bs./sq.in., or less per !oot depth of wax mass, and the concentration o! crystalline wax being less than substantially 20% by volume of the mass in which mother liquor is still present. The displacementstep is usually accompanied by the settling or compacting oi' the wax mass from which the mother liquor is being removed, but such compacting is controlled to prevent the concentration of crystailine wax in the mass !rom exceeding substantially 20% by volume of the mass. This control is obtained by the proper adjustment of the quantity of wax crystallized from the mother liquor to form the initial wax mass, the rate and degree of cooling, the diflerential pressure required tor displacementand the gravity diflferentials between wax. mother liquor and displacing liquid. Upon completlon of the displacement operation the solvents employed may be separated from the oil and wax iractions bydistiilation.

In carrying out the process, it is necessary to' control the quantity oi wax in the mother liquor so that the crystalline wax content of the mass resulting from the chilling oi the mother' liquor will not exceed substantially 10% o! any unit volume of the mass at the beginning ot the displacement operation. In most instances, it has been found that the crystalline wax contained in the wax mass at the beginning of the displacement step should be oi' the order oi from 1% to6% by volume, and prei'erably oi! the order of !rom 2.5% to 4.5% by volume; it may, however, be as high as 10% by volume depending upon the character or the wax crystals. Furthermore, in general, the diflerential pressure required in eflecting displacement does not exceed substantially 5 lbs/sq. in. per unit (1 foot) depth o! .the wax mass, and usually at the outset does not exceed 2 lbs/sq. in. It is to be understod, however, that at some stages of the operation, and particularly during the letter part thereot, the pressure may be somewhat in excess of 5 lbs/sq. in; per 1 i'oot depth oi' the mass. In accordance with the method above mentioned, we are able to prepare waxes containing less than 2% oi oil, and in general, less than substantialy 1% ot oil.

Example I .-Following the procedure above set torth, 35 parts by volume of a wax-hearing East Texas intermediate distlllate having a Saybolt universal viscosity of 57 seconds at 210" F. and an A. P. I. gravity of 25.3 at 60 F., was admixed with parts by Volume of ethylene dichloride and heated to a temperature of about l20 F., until a homogeneous solution was obtained. This solution was chilled, with agitation, to a temperature of about 60 F., whereupon a portion of the wax crystallized to form a wax mass having the oil-solvent mixture containing uncrystallized wax dispersed therethrough. The oil-solvent mixture or mother liquor was then displaced from the wax mass at a temperature oi' about 60 F., without substantial agitation and undena low diflerential pressure, by means of a wash liquid such as 88 A. P. I. petroleum naphtha. The washed wax, after removal therefrom of wash naphtha, by distillation, had an A. S. T. M. melting point of 153" F., a reiractive index of 1.434& at 176 F. (80 C.),

, and an oil content of 0.6%.

The oil-solvent mixture or mother liquor displaced from the wax mass aioresaid was further diluted with ethylene dichloride to give a solution containing 20 parts by Volume of oil-wax stock and 80 parts by Volume of ethylene dichloride. This solution was then chilled to about O F., a portion oi the wax crystallized therefrom, and the residual mother liquor displaced with 88" naphtha at 0 F., in the manner above described. The resulting washed wax, after removal of the naphtha, had an A. S. T. M. melting point of 1l9.5 F., a. reiractive index oi 1.437& at l7 F.

. (80 C.) and an oil content of 02%. e

This substantially oil-free wax was therfractionated by sweating, the properties oi then-actions being shown in Table I below.

Table I Final cut N sweating Percent A. S. T. M.

' temperyield melting pt. a C

ature (w 116 38. 7 112. 5 44. 5) 1.!388 116 17. 5 118. 0 46. 3 1. 43& 122 4 120. 5 49. 2 1. 4365 128 9. 9 1%. 0 52. 3 .l. 4353 1% 10. 5 133. 0 (56. 1. 4346 By way of comparison, there is shown in Table II the properties of the wax fractions obtained by the sweating of a substantially' oil-free commer- A cial paramn wax having an A. S. T. M. melting point oi 122.5 F. (50.4 C.) and a rei'ractive in-- dex oi 1.4228 at 80" C., which was produced by sweating paramn slack wax in the conventional manner.

Table II Final cut No sweating Percent A. B. T. M. m"

' peryield melting pt. C)

ature F. F. 'C', 114 14. 5 111. 5 43. 8 119 21. 0 116. 5 46. 5 124 0 121. O 40. 6 129 16. 1 125. 5 52. 0 134 13. 9 130. 0 54. 0 134 11. 5 136. 5 57. 5

our process.-as compared with the fractions resulting from .the sweating oi' the commercial peramn wax. Rei'ractive indices at 80 C., are shown as the abscissae and the melting points as determined by the A. s. T. M. method No. D-87-22 are shown as ordinates.

Upon determining the refractive index-melting point relationship for a large number of common waxes and parailin hydrocarbons, it was round that substantially all of the waxes and hydro- V carbons tell within a band or zone deflned by diagonal !ines whose equations are n=1.400( l+0.00044T and n=1.4070+0.00044T,

respectively, wherein "n" is the reiractive index at 80 C.. and "T" is the A. S. T. M. melting point. The series oi diagonal lines shown in Fig. 1 are drawn parallel to the line whose equation is and difler !rom one another in their re'i'ractive index intercepts by 0.005.

It will be noted from curve A, which represe'nts the wax tractions as obtained in accordance with Example 1 described hereinabove, that as the melting point increases the reiractive index decreases, whereas in curve B, which represents the wax !ractions obtainedby sweating the commercial parafln wax of Example 2 (given below), it will be seen that the relationship is reversed, i. e.. with increase in melting point the refractive index also increases. wax iraetions on curve B, corresponding substantially in melting point with those on curve A, fall within the band deilned by lines whose equations are n=1.4035+0.00044T and ;=1.4058+0.000 44T respectively, the maximum difference in the abscissae intercept values being 0.0023, whereas 'the wax iractions on curve A fall within the band deflned by the lines whose quations are 1=1.410+0.00044T and 1=1.4192+0.00044T respectively', the maximum difierence in the abscissae intercept values being 0.0092.

The following examples, in conjunction with the curves shown in Figures 2 and 3 of the draw ings, will further illustrate the results which may be obtained in accordance with our invention.

Example 2.-An East Texas paramn distillate was distilled to yield a wax-hearing traction comprising the st 40% of the distillate. From this fraction there was separated at a temperature of about -20 F.. and in accordance with the lst procedure set rorth in Example 1, a substantially oil-free wax having an A. s. T. M. melting point oi' 93 F. (33.9 C.) and a refractive index of 1.4205 at 176 F. (80`C.). This was iractionated by sweating to give a series oi cuts having the properties indicated in Table m, the relationship Table III Refmctive Cut No.

Reierrlng now to Fig. 1 oi the drawings there is illustrated graphically the novel relationship between the melting points and -reiractive indices oi' the wax iractions produced in accordance with Example 3.-The initlal substantially oil-free wax produced in accordance with Example 2, having an A. s. T. M. melting point oi 93' I".

(33.9 C.) and a reiractive index of 1.4205 at 176 15 I'. '(80' 0.), was distiledunder reduced praure m/m) to yieida bottoms or residusl wax oomprising 333% o! the charge and having an A. 8. '1', M. meting point oi 1143' I". (45.0' c.) s and a retractive index oi' 1.42 at 176' P.-(O0' 0.). 'nxis resida 'ox was i'ractlonated by sweating' to give a series of the properties indicated in Table Iv, the relationhip' ot the retrsctive indices to the meting points being &mmm

!his Musli! oil-!ree .wax was iractionated by meeting ata temperature of !rom 147 -F, to

gravity ot 25.5 at 60' r., there was produced by the first step o! the "diplacement" method utorrementioned, at a separation temperature o! about 60' F.. a substantially oil-tree wax having an A. 8. T. M. melting point oi 153.8 l". (O'L'P GJ'. a retractive index ot 1.434& at 176' I". (80' 0.), and an oil content of 0.496. This mbstsntiaiiy oil-!ree wax was suhsequently sweateq at temperature oi' from 151 1". to 162 F., and' a series ot outs were produced having the properties indicated in Table V, the relationship of rerractive indices to melting points being shown by curve E of Figur-e 2 of the drawings.

Table V yieid cut No.

Example 5.--'I'he emux or mother liquor' obtained by displacement !rom the wax of Example 4' was chilied to about o F., and a second wax !raction was cry'staliized therei'rom and washed !ree oi oil. This wax !raction had an A. 8. T. M. melting point of 119.5 F. (4831" c.), a refractive index of 1.4374 and an oil contento! 03%. Upon sweating this wax !raction at a temperature ot !rom 107 I". to 127 F., there was produced a series ot cuts having the properties indicated in Table VI, the relationship ot the retractive indices to the melting points beme illustrated by curve I" of Fill. 2 of the drawings.

Table VI Peeent A. s. r. M. WM 05 yisid melting pt. 393

F. 'a sa7 zs &7) mss 17.5 so u aso '22.4 mr 40.2 1.436& 9.9 mo sas 1.4358 mr mo (seo 1.43

Example d.-From a wax-bearing petrolatum stock having a Saybolt universal viscosity of 69 'Il seconds at 210 F., and an'A. P. I. gravity of 27.5"

o shown by c'urve D oi' m. 3 oi' the drawing& OTI'., and a series' of outs were produced having TM N ,the properties indicated in Table VII, therelationships ot the refractive indices to the melting i" points being shown by curve G of Fig. 2 of the cut N Pm: A 5.1'. u m dr'awings. v I." o (W 0 Table VII r. c e V Reli-active iz:: :e: e: ::a m s Ju o s &u um i mo (sa: Lmo r. c !sample 4.-"rom a wax-bearin'g intermediate ?li i gla lubricating distiliate havin: a Sayboit u 335 1 133 viscosityotM seconds at 210' Land anAEI.

Example' it-The emux or mother iquor ob'- by dispiacement-!rom the-war: of Example 8 chiiled to about 5" F., and a second wax ::action was crystaliized theretrom and washed !see of oil. .Thisw'ax !rsctiou had'an A. S; T. M. .meitin point of 121.03 F. (49.0 C.) a retractive lhdex o! 1.447!! at 178 1". 80" C.) and an oil ,ontent of 03%. Upon sweating this wax fraction at a temperature o! from 109 I". to 149 F.,there was produced a series of cuts having the properties indicated in Table VIII, the relationshipof the re- !raction indicesto the melting points being shown in curve H of lig. 2 oi' the drawings.

Table VIII Refractive Percent A. s. T. M. Ct No. index yield melting pt a) F. C. 30.3 1120( 1.4400 28.8 117. 0 (47. 2 1. 408 29. 9 124. 0 (51. 1\ 1. 4476 11.0 133.615& 3) 1.4460

Example 8.--From a. iracton ot a pramn distiilate having a Saybolt universal viscosity o! 90 seconds at i00 F., and an A. P. I. gravity oi 30.5' .at 80' F., there was produced, substantiaiiy in accordance with the lst step oi' the 'fdisplacement" method described` in connection with Example '1, at a separation temperature oi' about 40 P., a su'bstantially oil-tree waxhaving an A. S. T. M. meting point of .132 F; (55.5 C.-), a retractive index of 1.4286 at 176 F. (80 C), and an oii .content of 0.6%.. This substantiailyoil- !ree wax was -tractionated by sweating at a temperatute o! from 122 F. to 133" F.. and a series of outs was produced having the properties indi cited 'in Table IX, the relationship of the .retractiveindices to the meiting points being shown by aoaaees t Example 9.-The eiiiux or mother liquor obtained by displacement from the wax of Example 8 was chilled to about 0 F., and a second wax fraction was crystallized therefrom and washed free of oil. This wax fraction had an A. S. T. M. melting point of 106.5 F. (41.4 C.) and a refractive index of 1.4262 at 176 F. C.).` Upon sweating this wax fraction at a temperature of from 102 F. to 122'F., there was produced a series of outs having the properties indicated in Table X, the relationship of the refractive indices to the melting points being shown by curve J of Fig. 3 of the drawings.

Table X I Rciractive Percent A S. T. M. m .yield melting pt. g

Example 10.-Approximately 50% of the initlal oil-free wax of Example 4 and 50% of the initial oil-free wax of Example 5 were admixed to form a homogeneous product having an A. s. T. M. melting point of 146.0 F. (63.3 C.) and a refractive index of 1,436? at 176"' F. (80 C.). This product was fractionated by sweating at a temperature of from F. to F., and there was produced a series of cuts having the properties indicated in Table XI, the relationship of the refractive indices to the melting points being shown by curve K of Fig. 3 of the drawings.

It will be seen from the above examples that, in general, the wax outs or fractions produced in accordance with our invention are characterized by the fact that as the melting points increase, the refractive indices decrease, which relationship is not characteristic of the waxes produced by the conventional sweating processes applied to the common paraflin waxes, for example, the sweating of commercial paraffin wax. It will further be seen that the wax fractions produced in accordance with our invention differ from one another in their refractive index intercepts to a much greater extent than do those of the wax fractions produced by the sweating of known waxes, for example, commercial paramn wax. In the equations of the type relating refractive index to melting point, i. e., n=x+0.00044T, where n" denotes the value of the refractive index, "T" denotes the melting point in C., and "x" denotes refractive index intercept values, the difierence in the value of x for different wax fractions, produced in accordance with our invention, may be of the order of 0.0025, 0.005, 0.0075 and 0.01 or more, whereas the diflerences in such values for the known waxes are usually of the order of 0.002 or less.

Furthermore, the wax fractions produced in accordance with our invention difier from the common 'hydrocarbon waxes oi' corresponding melting points in that they possess much higher boiling points than the corresponding waxes heretofore known; their refractive indices are substantlally higher than those oi the corresponding known waxes; their molecular weights are much higher than those of the corresponding known waxes, and they differtrom the known waxes in other properties such as hardness, tackines's and plasticity. I I

We have found, as another aspect of our invention, that in order to produce the highest yield of high' melting point wax oi de'sired properties,

and the highest yield oi low melting point wax of' desired properties, frcm a'mixture of hydrocarbon'waxes, it is preferable to eflect a separation of substantially all of the oil from the wax and to separate or segregate the higher melting waxes, as one or more fractions, from the lower melting waxes, as one or more fractions, prlor to subjecting such wax to Iractionation by sweating. This separation or segregation may be eflected by the "displacement" process atorementioned,` or' by other methods involving, !or example, solvent treatment, recrystallization or distillation. This aspect of our invention may be illustrated by the following example.

From a wax-bear'ing lubricating oil distillate there was producedby a single "displacement" operation, a substantially oil-free wax fraction having an A. S. T. M. melting point of 146 F., and containing high and low melting point waxes. This fraction was then sweated to produce a wax cut having a melting point of 150 F. and the yleld obtained was of the order of 33% by weight, based on the total quantity of wax separated from the distillate.

Upon subjecting the same wax-hearing distillate to a double or 2 stage "displacement" operation at two different temperatures, whereby the higher melting waxes were segregated in the lst fraction and the lower melting waxes in the 2nd fraction, there was produced two substantially oil-free fractions having A. S. T. M. melting points oi! 153.8 F. and 119.5 F., respectively. The iraction having the higher melting point was then sweated to produce a wax cut having a melting point o! 150 F. and the yield obtained was of the order of 54%, by weight, based on the total quantity of wax separated !rom the distillate.

It will be seen, from the above example, that the yield of 150 F. melting point wax was markedly increased by separating the wax initially present in the distillate into at least two tractions. prior to sweating that !raction containing the higher melting point waxes. substantially the same method may be applied to the recovery of high yields of low melting wax, when the initial stock comprises a mixture of the waxes of varying melting points.

Our method of treatment may be applied to a variety of waxes or wax-hearing oils, for example, viscous wax-hearing distillates and residuums, and particularly wax-hearing oils having Saybolt universal viscosities at 210 F., within the range of from about 40 seconds to about 400 seconds. to produce substantially oil-tree waxes having the novel relationship between reiractive indices and melting points hereinbefore set iorth. The step of fractionation by sweating may be can-led on at any suitable temperature, and preferably within the range oi' from about 85 F. to about 180 F.

While, in general, we have described our step of segregation or "displacement" to produce submmm oil rree wu .mixtures, utiliing ethyland s. solvent icr the oil. reducing ths temperene dichloride sud 88' nsphths sfsolvents, we do n'ot intend to limit ourselves theretc, hut'msy enploy &ny ccnventionsi dewsxing soivent or solventnixtre, for example, nsphth, alcohol, neetone, scetone-benc; snd the like. s well u the iqeflednornniy hydrocsrhcn such ss ethsne, propcne, butane. pentsne and theike; or mixtures thei-eci.

Eerein, 'and in the sppended clsims, the term "substantisily oil-free` wu" is to he understo'od to comprehend ws: which contains less than suhstsntisuy. 2% by weight ci' cil. as determined in occcrdance with the method disciosed in the copending application of B. W. l erris, Serial No. 4,157, med Jsnusry 30. 1935 anii entited "Treat- !nent of m.

whstwcclsirniszv. u g

i. In a 'process !or treting a hydrocrbon oilwx mixtnre, the steps which comp'ise segregating from said mixture, a !racticn containing p the higher meiting wex components thereo! substantinlly tree ot oli and s, !rsction contsining the lcwer nelting ws: components thei-eo!- shstsn-` tinly free of cil and subjecting st least cne oi saiiiracticnstcswesting. e

2. In s. process for tresting hydrocsrbon cilwsx mixture containing higher meting and lower meiting wsx components the steps which comprise io-ming s. homogenecus mixture c! cu, wu

sture c! the mixture to cause higher melting ws: components to crystalize, seperting the mixture ci oil. sclvent and lower melting ws.: components rrom the crystsiied ws: and thereby producing a substantially cil-!ree higher melting wax irecticn and subjecting said higher melting trection to sweating'.-` v i 3. In s process i'or trcsting s hydrocsrbon'cilwax mixture containi z'hiher metingan'd lower melting' ws.: components, the steps which'ccmprise io-rnings hcincgemeousmixture c! and a solvent !or the oil, reducing the temperature ci the mixture to cause higher melting wax components to crystalize, separating the mixture oi' cil, solvent and iower melting waxcomponents !rom the crystsied wax to produce a substantially oil-free higher melting ws: irsction. turther cooling said separated mixture ot oil, scvcnt and lower melting wa: componentsto cause lower melting wax components tcc'ystallize, separating the remaining ci-'scivent mixture !rom sid crystsnized lower'meiting ws: components and thereby producing a substsntlsliy cil-free lower meiting wsxi'raction, and subjecting st least 'cne c! said substantially oil-!ree wx'i'rsctions to sweeting. v

BEYMOUR W. mms. WILLARD I'. HOUGETON; HENRY C. COWLES, J. 

